av_image_copy: check for av_image_get_linesize() failure.

Fixes CID703722
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavutil/imgutils.c

@@ -276,6 +276,10 @@ void av_image_copy(uint8_t *dst_data[4], int dst_linesizes[4],
         for (i = 0; i < planes_nb; i++) {
             int h = height;
             int bwidth = av_image_get_linesize(pix_fmt, width, i);
+            if (bwidth < 0) {
+                av_log(0, AV_LOG_ERROR, "av_image_get_linesize failed\n");
+                return;
+            }
             if (i == 1 || i == 2) {
                 h= -((-height)>>desc->log2_chroma_h);
             }